Method of making roadways



June 30, 1925 1,544,440

S. E. FINLEY METHOD OF MAKING ROADWAYS Filed Dec. 15. 1924 Patented June 30, 1925.

UNITED STATES SAM EVERE'IT FINLEY, OF ATLANTA, GEORGIA.

METHOD OF MAKING -ROADWAYS Application led December 15, 1924. Serial No. 755,986.

To all whom t may con-cern.'

Be it known that I, SAM E. FINLEY, a citizen of the United States, `residing at Atlanta, in the county of Fulton and State of Georgia, have invented certain new and useful Improvements in Methods of Making Roadways; and I do hereby declare the following to be a full, clear, and exact description ofy the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The invention relates to a novel method of constructing roadways and the like of bituminous cement-aggregate concrete and has for its object the production of a road structure of uniform texture, density, durability 'and imperviousness tozweather` conditions, at a minimum cost. To this end, the invention comprises, spreading the ,mineral aggregate, of proper character, upon the prepared subgrade of the roadway in a uniform layer between edge defining forms placed temporarily in series longitudinally of the roadway, compacting the aggregate, preferably by rolling, removing the forms along one edge of the compacted mineral aggregate layer, applying a coat of bituminous binding medium to the longitudinal section of the roadway adjacent -said edge and to the vertical face of the aggregate layer constituting said edge, then, preferably. finishing the coated longitudinal strip by the application of the usual casting of stone chips, removing the forms on the opposite side of the aggregate layer and similarly treating the adjacent longitudinal section by the application of a coating of the binding medium to the top surface and the lateral face or the verticalI edge, and ultimately finishing the coated longitudinal section. as in the first instance. The invention is illustrated inthe accompanying drawings, in which:

Fig. 1 is a transverse section of a roadway under construction, showing the application of loose broken stone between the removable shoulder forms.`

Fig. 2 is a similar view showing the construction aft-er the aggregate layer. has been rolled.

Fig. 3 is a similar section illustrating the mode of applying the binding medium to the surface and shoulder or vertical edge of one longitudinal section of the compacted layer of aggregate.

the aggregate, it has been customary to lay temporary forms longitudinally of each side of the roadway to define the marginal edges of Athe aggregate layer, the forms being retained in position until after the aggregate has received an application of .binding meJ dium. It has been regarded as necessary to permit the edge defining forms to remain in position, in order to prevent the mineral aggregate from raveling out at the edges during the rolling operation, prior to the application of the` binding medium, the forms serving to maintain the proper cross section and contour of the aggregate layer. The inherent object-in to this practice is the fact that the binding medium, which is highly ductile and adhesive,will adhere to the forms as well as the aggregate, and when it is attempted lto remove the forms, the portions of the aggregate which. are adhesively attached tothe forms by the binding medium will be pulled out of the body of the aggregate layer, thereby impairing the latter and rendering it necessary tu replace the displaced material, both the aggregate and the binding medium, which operation involves considerable expense and trouble. Furthermore, when the edge defining forms are permitted to remain in position` until the road.' surface is finished, in the operation of applying the finishing coat of stone chips, it is practically impossible to keep some of the chips from falling on the vtops of the forms and, when the roller in the final compacting operation comes in contact with these chips, the latter' will prevent a uniform compression of the road structure bv the roller, as the wheels or the drums of the latter will be prevented from maintaining a uniform contact with the road surface by the stones on the tops of the forms. .so that the road surface is impaired and the concrete body will necessarily be of non-uniform density, compactness and cross section.

The instant invention is effective in avoidlng the diiiiculties and objections inherent 1n the former practice and enables thoroughly homogeneousand uniformly compacted layers of concrete to be applied to the road under conditions that willinsure the maintenance of the proper cross section of the .cemented body .of aggregate, with sharply defined vertical lateral edges, which may, if desired, be fashioned to constitute integral headers or curbs by `the application of an additional quantity of binding medium to the edge sections.

The mode of procedure is clearly illustrated in the drawings in which 1- represents the site of the roadway or equivalent structure, which is worked to proper grade and contour to receive the concrete. Placed in two parallel rows and. running longitudinally of the roadway are edge dening forms 2 2, which may be of wood or other suitable material, preferably having a thickness equal to that of the initial concrete slab, the forms being fixed or anchored in position by any suitable means, but being readily removed. Between4 the forms, which are spaced apart a distance equal vto the width of the roadway, is spread a layer of broken stone, or other suitable mineral aggregate, of proper grades and sizes, the top surface of the layer being preferably worked to an approximate contour. This layer of broken stone confined between the forms 2 2 is then thoroughly rolled /to compact the same and to effect a substantial mechanical bond between the various elements of the aggregate, as'r illustrated in `Fig. 2. The compacted layer of aggregate is 'self-supporting, so that, when the forms 2 on the right-hand side of the road, for example, as illustrated in Fig. 3, have been removed, the vertical lateraledge of the layer of broken stone will remain intact. After the righthand forms have been removed, a suitable binding medium, preferably in the form of highly heated lstable bitumen or asphalt, is

applied to the right-hand section of the minl eral aggregate layer, by the method and apparatus for treating roadways disclosed in my prior Patent No. 1,341,458, dated May 25, 1920, the apparatus involving a tank wagon, such as 10, having a laterally disposed spray header 11 adapted to distribute t-he binding medium uniformly over the surface of the right-hand section of the layer of mineral aggregate, the spray header also being provided with one or more terminal or end spray nozzles 13, so constructed and arranged as to deliver the binding medium against the vertical lateral face of the layer of aggregate. Preferably, multiple nozzles 13 are used to supply an additional quantity of asphalt to the lateral edge and vertical face of the aggregate layer, thereby producing what is, in effect, an integral header or curbing along the edge of the roadway. While the application of the binding medivum to the right-hand longitudinal section of the aggregate layer is being elected, the vehicle traverses the left-hand untreated section of the aggregate layer, and in order to prevent the aggregate'being displaced laterally by the passage of the vehicle, the lefthand forms 2 are retained in position. After the right-hand section has been treated with binding medium, as described, any desired form of surface treatment or finish may be applied, such, for example, as the customary casting of stone chips, with or without the application of a seal coat of binding medium, as conditions'may require, the left-hand longitudinal section of the aggregate layer is reworked, if necessary, to remove the ruts or other impairments produced by the wheels of the tank'wagon, and the latter is then traversed over the wholly or partially finished right-hand section of the roadway to distribute the binding medium to the left-hand section of the roadway, coating the surface and the lateral edge or shoulder of the aggregate layer as in the irst instance, the forms 2. along the lefthand edge of the aggregate also having been removed prior to the application of the binding medium. The left-hand section is then finished in the same manner as the right-hand section and, if necessary or desirtour, after which earth or other suitable material may be deposited laterally of the paved surface on both sides and finished to the desired contour, or, if preferred, permanent headers or gutters bounding the lateral edges of the roadway may be constructed.

lli/'hat l claim is:

1. The method of constructing roadways comprising placing edge defining forms longitudinally of the road site, spreading mineral aggregate between the forms to the desired depth, compacting the aggregate, removing the 4forms along the edges, and applying a coating of binding medium to the surface and to the vertical edges of the aggregate layer.

2. The method of construct-ing'roadways comprising placing edge defining forms longitudinally of the road site, spreading mineral aggregate between the forms to the desired depth, compacting the aggregate, removing the forms along one edge, applying a coating of binding medium to the adjacent longitudinal section of the surface -and to the vertical edge' of the aggregate gitudinally of the road site, spreading mineral aggregate between the forms to the desired depth, compacting the aggregate, removing the forms along one edge, applying a coating of binding medium to the ad- 'acent longitudinal section of the surface and to the vertical edge of the aggregate layer, finishing the'coated section, then removing the. forms along the other edge, similarly treating the surface of the ad]a cent section andthe lat-ter. edge, and inally finishing the second coated section.

4. The method of constructing roadways comprising placing edge defining forms longitudinally of the road site, spreading mineral aggregate between the forms to the desired'depth, compacting the aggregate, re-

quantity of binding medium to the vertical edges of said layer.

In testimony whereof I aiix my signature.

`SAM EVERETT F INLEY. 

